103kW/125kw TDI PD Piezo Siemens injector failure thread

[Greg Roles]

Hey all,

There's growing evidence that the Siemens injectors fitted to the MKV 125kw engines are starting to fail across the board. Seems to affect the Passat mostly, but as this is basically a GT TDI engine with a counter shaft balancer, the injectors are the same. It seems to be the pizeo portion of the injector that fails, and VW are very aware of the problem and offering revised injectors at exchange with your old ones. I'd like to start a thread to both record the numbers of actual failures, and to inform of any options / fixes as they come to light. I'm doing a lot of research into it, as heck, mine could go at any time, and I'm wondering if I even bother with extended warranty given how modded my engine is starting to look, let alone what it'll look like this year when the big stuff finally happens.

Here's the first of a few interesting articles I've found, but across the world, there are people from Skoda, VW, Seat and even Audi up in arms about the issue. No doubt aftermarket injectors will come, and given the cost VW will no doubt charge, it's the way I'd go. At this stage all I've been able to find is they cost $400ish pound EACH in the UK, love to know what the going price is here.

https://sites.google.com/site/1810ma...iezo-injectors

Also interested if anyone can tell me why the swapout with warranty cars seems to also include the wiring harness - is it different, or just worth doing while you're in there?

[Greg Roles]

One of many forums reporting on the problem. The GREAt news is there's a link to a UK company that can repair the Siemens. I've sent them an e-mail and will let you know what they say.

UKpassats.co.uk • View topic - Faulty diesel injector?

and the company link....

AP Diesels Ltd - Home

[nutttr]

According to the ukpassats link they may be going to ground when they fail - Depending on the voltage/current/wire guage, etc, going to ground may be damaging the wiring, hence swapping it out. It's crazy they are that expensive though and i'm sure it's only a matter of time before they find a way to retrofit different injectors...

[Transporter]

My 2c.

https://sites.google.com/site/1810ma...iezo-injectors

[gldgti]

thats a great link transporter, thanks!

[kaanage]

desertstorm linked to it in the thread linked in the 2nd post by CogDoc.

One of the Passat owners, here, with a 103kW TDi posted that he also had the same failure, though, and I thought those didn't use the piezo-electric controlled injectors

[Transporter]

LOL, I completely overlooked that Greg already posted that link. Don't worry Greg, I'll clean it up.

[OilBurna]

mine failed 103kw tdi I was of the understanding the injectors were the same for the 103kw and 125kw PD's..

[Greg Roles]

Nope they ate different, with the supposedly notorious pizeo part being a 125 thing, may have become common at some stage during lifecycle though. Very interesting if 'normal' 103 injectors are dying too, I thought they were quite reliable?

The more links and info, the better Miro, it's going to take a combined effort to solve this!

[OilBurna]

for the PD versions they both use same injectors, however the 125kw uses a higher pressure, also differences in the ECU and turbo? and the 125kw has the DPF. From wiki and other links they are otherwise the same.

ere is the difference between the 2 TDI engines - the outputs vary within each of the specifcations depending on ECU. The new 2.0 TDI as far as I know, does not have a Variable Geometry Turbo (VGT). This engine is being phased out over the next few years, in favour of an all new design, with the Pump-Dusse injection system being replaced with a Common Rail injections system.

2.0 TDI with 103 kW: 209 kph is the top speed of the 103 kW / 140 bhp (at 4,000 rpm) Passat 2.0 TDI. The four-cylinder engine develops a maximum torque of 320 Newton metres as low as 1,800 rpm, and takes just 9.8 seconds for an easy 0-100 kph sprint before reaching the top speed of 209 kph. Average consumption: 5.9 litres. This TDI performance level can be combined with a diesel particle filter.

Numerous details were modified in order to facilitate the use of an optional, additive-free diesel particle filter in the 2.0 TDI. Some examples: in order to allow the DPF to be mounted as close to the engine as possible, the position of the exhaust turbocharger was changed. The pressure with which the pump-jet element injects fuel into the slightly modified combustion chambers was also increased to as much as 2,400 bar. In addition to this, the pumping characteristic of the pump-jet was modified to allow additional injections for the thermal regeneration of the filter or other reasons. Engineers concurrently succeeded in further reducing the oil consumption, another measure to increase the efficiency of the DPF. The diesel particle filter is maintenance-free, and forms a modular unit with the oxidation catalytic converter.

2.0 TDI with 125 kW: The second 2.0 TDI, fitted with highly innovative piezo pump-jet high pressure injection and a compensator shaft, is a completely new design. This very quiet, four-valve TDI has an output of 125 kW / 170 bhp (4,200 rpm), develops a torque of 350 Newton metres (1,800-2,500 rpm), and accelerates the saloon to 100 kph in just 8.7 seconds. The top speed is 223 kph. Here, too, the average fuel consumption is low, at 6.1 litres over 100 kilometres.

Technically, the 125-kW TDI, with its switched induction manifold for turbulence control, is based on its 103-kW equivalent without diesel particle filter. This cultivated engine is the world's first piezo pump-jet TDI. Further technical features are two compensator shafts (reducing secondary vibrations by up to 80 percent), a maintenance*free diesel particle filter, and an injection pressure of up to 2,200 bar. The specific power of the 2.0 TDI, at 62.5 kW per litre, is a new best. Although the new TDI has power and convenience characteristics that come very close to those of a five- or six*cylinder turbo-diesel, the consumption and emission figures are in the low four-cylinder range.

Technologically, a central factor in the achievement of high power and convenience values together with low consumption is the use of the newly developed piezo pump-jet elements. Using one of the piezo actuators to control the high-pressure valve of the pump-jet permits:

· -very high injection pressure, and thus low emission and optimum specific power.

· -ideal hydraulic efficiency because of the very small high*pressure volume.

· -ideal injection process.

· -very precise, low-volume pre-injection at a low pressure level.

· -flexibly controlled pre- and post-injection and injection intervals.

· -low injection noise.

A further innovation in the TDI is the use of a newly developed compensator-shaft module. The term "module" is easy to explain: the two counter-rotating compensator shafts (turning at twice the engine revs), together with the oil pump, form a separate module located under the cylinder crankcase. The compensator shafts noticeably reduce the amount of vibration that is transmitted to the bodywork.